1. Field of the Invention
This invention relates to devices useful for the controlled delivery of one or more beneficial agents to an environment of use. More specifically, this invention concerns such devices which are powered by lyotropic liquid crystals. This invention also relates to the controlled delivery of one or more beneficial agents to an aqueous environment of use through the use of such lyotropic liquid crystal powered dispensing devices. Further, still, this invention is concerned with devices for the controlled delivery of one or more beneficial agents to the physiological fluid of animals including mammals such as human beings.
2. General Background of the Invention
The desirability of controlled release of beneficial agents into an environment of use such as the physiological fluid of animals including mammals such as human beings is well known to those skilled in the relevant art. Controlled delivery of beneficial agents such as drugs can, for example, result in a relatively constant concentration of such agents in the physiological fluids of an animal instead of the more dramatic rises and subsequent decreases in concentration of such agents usually associated with periodic dosing. Furthermore, controlled delivery of drugs can eliminate certain deleterious effects sometimes associated with a sudden, substantial rise in the concentration of certain drugs.
A variety of devices for the controlled delivery of beneficial agents have been described. Certain of those devices employ the physical phenomenon of diffusion for their operation. Examples of such diffusion driven devices are disclosed in U.S. Pat. No. 4,217,898. Other devices have been described which operate with the principle of colloidal osmotic pressure. Examples of such osmotically driven devices are disclosed in U.S Pat. Nos. 3,845,770; 3,995,631; 4,111,202; 4,160,020; 4,439,196 and 4,615,698. Devices which employ a swellable hydrophilic polymer which polymer exerts pressure on a container and thereby forces drug therefrom is disclosed in U.S. Pat. No. 4,180,073. U.S. Pat. No. 4,327,725 discloses a device which employs a layer of fluid swellable hydrogel to force beneficial agent out of the device through a specified and defined passageway. Other hydrogel powered devices containing such a passageway for delivery of beneficial agents are disclosed in GB 2,140,687A.
Applicant's copending application Ser. No. 07/296,464, assigned to the assignee thereof and filed Jan. 12, 1989, now abandoned, entitled "Dispensing Devices Powered by Hydrogel" discloses dispensing devices, powered by hydrogel, for the controlled delivery of one or beneficial agents to an environment of use.
It is a object of this invention to provide devices for the controlled delivery of one or more beneficial agents to an environment of use. Another object of this invention is to provide devices powered by lyotropic liquid crystals which will effect the controlled delivery of one or more beneficial agents to an aqueous environment of use. Yet another object of this invention is to provide devices powered by lyotropic liquid crystals for the controlled delivery of one or more beneficial agents to the physiological fluids of an animal including a human being. This invention also has as an object the provision of a device to controllably deliver one or more beneficial agents which are insoluble or substantially insoluble in water or physiological fluids. Another object still of this invention is to provide devices powered by lyotropic liquid crystals which do not require a semi-permeable coating, but instead can employ a coating which is permeable to the beneficial agent. Further still, it is an object of this invention to provide devices powered by lyotropic liquid crystals which can assume a variety of shapes and sizes and devices which can be delivered to an environment of use in a capsule.
It is also an object of this invention to provide methods for the controlled delivery of one or more beneficial agents to an environment of use by administering to or otherwise placing the device of this invention into the environment.
These and other objects of this invention will be readily apparent to those skilled in the relevant art enabled by the disclosure herein.